so that values of \(\tau \)  could be generated from \(\tau =-\tilde{\tau } \ln (\xi _0)\) , where \(\xi _0\)  is a uniform random
number on \((0, 1)\)  [1]}. The characteristic time or
time-scale parameter \(\tilde{\tau }=\langle \tau \rangle \)  is
determined by the total rate:
\( \tilde{\tau } = R_\mathrm {tot}^{-1} \, .\) 
